Insulator



July 17, 1928.

R. P. JACKSQN4 INSULATOR Filed oct; 2, 19.22

INVENTOR /a//FLEe/rson.

WITNESSES:

AT'ToRNEY Patented July 17, 1928.

UNITED srarss taint .artnr rtree. f

RAY I. JACKSON, F EDGEWOOD PARK, PENNSYLVANA, ASSIGNOR T0 y'WES'llift- HOUSE ELECTRIC & MANUFACTURING COL VANIA.

INSULATOR.

Application filed October 2, 1922. YSerial No. 591,736.

My invention relates` to insulators and particularly to suspension insulators adapted for service in connection with high-voltage power circuits. Y

One object of my invention is to provide an insulator of the above-indicated character having an increased amount of creepage surface that is exposed to a direct washing action by rain, relative to similar insulators of l0 the prior art.

Another object of my invention is to provide an insulator of refractory insulating material that shall be so constructed asl to have a maximum surface area for given weight.

A further object of my invention is to provide a high-voltage suspension insulator that shall be simple and durable in construction, economical to manufacture and effective in its operation. v

'ln the development of high-potential insulators, various factors were introduced as the commercial voltages of power circuits were increased. In the earlier high-voltage systems, which are considered low-voltage systems, as compared with systems now in use and contemplated, the principal considerations were sufficient mechanical strength and thickness of insulation. After these considerations, came the feature of creepage surface which has beenmodiiied and extended -in various ways. Later, the idea. of-kecping arcs away from the insulating members was conceived and was put into` practice in the form of arcing rings and horns. lVith the advent of still greater' con'imercial po\vex.'circuil. `voltages, the con tinued endeavor toward improvement resulted in the suggestion of having the insulating bodies shaped to conform nearly as practicable to the electrostatic fields and, further, to so distribute the fields as to avoid concentration thereof.

The fact that deposits of dust and other foreign matter on insulators reduced the insulating properties thereof and caused breakdown at voltages below those at which clean insulators break down was recognized for a considerable time before the idea of providing the insulators with surfaces that could be washed by rain was suggested.

lThis feature of providing what has been termed washed surfaces is a comparatively recent development in the high-potential more nearly effected over the entire e.\;-

posed surface thereof.

In practicing my invention, I provide an insulator, similar to certain suspension insulators of the cap-and-pin type, in which the surface creepageor pctticoat portion, instead of merely extending to an outer limitlng position and ending there, is continued inwardly from near that position in such manner as to provideadditional creepage surface, in which the greater portion ofthe crcepage surface is subject to a direct washing action by rain.

Lhe insulator' is, further,-` so shaped and proportioned, and is soV constructed of substantially uniform thickness throughout, as to obtain a substantially maximum surface area for a given weight'of the material of which it is composed. l

rifhe single figure of the accompanying drawing is a side view, partially in elevation and partially in section, of an insulator embodying my invention. Y

rlhe insulator comprises, in general, a main insulating body member l, an auxiliary insulating member 2 within the member l, a metal-cap terminal membe 3 and a pin or tension member 4t for attachment, by a pin 5, to the nent adjacent similar insulator or other device. f

rlie main insulating body member l is provided with an end portion t3 of inverted substantially cup shape, over which the member 3 is secured .in position, as by cementing. From the open cud or perimeter ofthe cup-shaped portion (5, an annular por tion 7, similar to an ordinary petticoat member, projects, laterally and longitudinally to an outer limiting portion 8.

An annular portion 9 joins the portion 7 adjacent to the portion S and converges therefrom to a portion l() at one end thereof. This construction provides a hollow refractory member having a bulging portion which, in ordinary insulators of a similar type, is solid or lled.

rlhe portions 7 and 9 are ofV substantially Ytruste-conical shape but slightly curved to conform to equipotential and flow-line surfaces, respectively, in Vaccordance with certain prior art. Washing will take place over thel entire surface of the portion 7, and over the greater surface of the portion 9, by di rect impact of rain. Thus, nearly all of the outer exposed surface of the insulator will be subject to washing, while the innersure face, by reasonof the constricted mouth of the member' l., will be protected against undue deposits of dust and other foreign matter. Since the member l has substantially uniform relatively thin walls, the auxiliary insulating member 2, which may be cemented in position in thecup-shaped portion 6, may be added to provide sufficient insulation, .for certain voltages, at the head of the insulator, between the members 3 and 4:.

The pin or tension member l: is provided, at one end, with an enlarged or anchor portion 12 for mounting, as by cementing, in the member 2 or in the portion 6 and, at its other end, with an attachment portion for the reception of the pin and the next adjacent insulator.

While in certain localities, the usual insulator becomes very dirty, or deposited with dust, and is thereby rendered ineflicient, an insulator constructed in accordance with my invention will be periodically cleaned and, in general, be maintained at much higher state of efficiency from this cause than insulators of the prior art.,

Further, by reason of the particular construction and the uniformity of thickness of the walls of the member l, the latter, not only provides a substantially maximum surface` areafor a given weight, but facilitates its construction in porcelain. In other words, the difficulties attending the tiring of uneven 11i-asses of refractory material are removed and an insulator of uniform quality is obtained.

Vhile I have shown and described a particular form of my invention, various changes and modifications may be made therein without departing from the spirit and scope thereof and I desire, therefore, that only such limitations shall be imposed as are set forth in the appended claims.

I claim as my invention:

l. An insulator comprisingl an insulating member including a head, a portion having an annular water-shed surface diverging from the lower end of the head and a lower portion `having an annular creepage surface of relatively great length and area sloping inwardly and downwardly from a position closely adjacent to the outer perimeter 0f said water-shed surface in such position as to receive driving rain directly, said watershed .surface portion projecting only slightly beyond the upper end of said lower portion to provide a water-drip portion preventing the passage of a continuous stream of water along the water-shed and creepage surfaces but permitting the washing of the major portion of said creepage surface by driving rains.

2. An insulator' comprising an insulating member including ahead, a portion having an annular water-shed surface sloping outwardly and downwardly from the lower end of the head and a lower portion having an a mular creepage-surface of relatively great length and area sloping inwardly and downwardly from Ya position closely ladjacent to the outer perimeter of said watershed surface, said water-shed surface portlon projecting only slightly beyond the upper end of said lower portion to provide a waterdrip portion preventing the. formation of a continuous stream of water along the watershed and creepage surfaces but permitting the major portion of said creepage surface to be washed by driving rains.

An insulator comprising an insulating body having a head portion, an annular surface-creepage water-shed portion sloping downwardly and outwardly from the lower end of said head portion and an annulary surface-creepage flange of relatively great length and area sloping downwardly and inwardly from a position closely adjacent to the outer perimeter of said watershed portion, said water-shed portion projecting` only slightly beyond the upper end of said iiange and constituting a water-drip portion to prevent the passage of a continuous water stream along the water shed and the outer surface of the flange but permitting the washing of the major portion of said outer surface by driving rains. Y

In testimony whereof, I have hereunto subs `ribed my name this 27 th day of Septen'rber 1922. Y

RAY P. JACKSON. 

